1. Field of the Invention
The present invention relates to a navigation device, and more particularly to a system for displaying traffic information in a car-mounted navigation device.
2. Description of the Related Art
Traffic information has been recently more and more utilized in a car-mounted navigation device along with the spread of the vehicle information and communication system (VICS). For example, Japanese Laid-open Patent Application No. 2004-108849 discloses a system for displaying traffic congestion information on a plurality of locations on a map screen. In this system, the traffic congestion information of the same time period, for example a current time, is displayed with regard to a plurality of locations.
What users want to know, however, is the traffic congestion information of a future time, at which the users will arrive at a location (hereinafter referred to as a predicted arrival time). In the above-mentioned system, the traffic congestion information of the same time period, for example a current time, is shown on any locations on a display map, and therefore it is impossible for the users to accurately know the traffic congestion information of the predicted arrival time at each location on a route.